Stringless guitar-like electronic musical instrument



Sept. 5, 1967 T. P. wou. 3,340,343

7 STRINGLESS GUITAR-LIKE ELECTRONIC MUSICAL INSTRUMENT Filed May 6, 1964 4 Sheets-Shet-l F 6, GENERATOR smme SUBCHASSIS KEY F: 6.1.

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STRINGLESS GUITAR-LIKE ELECTRONIC MUSICAL INSTRUMENT 4 Sheets-Sheet 5 INVENTOR THOMAS P. \UOLL WLMWH X/ g ATTORNEYS United States Patent O Ohio Filed May 6, 1964, Ser. No. 365,438 16 Claims. (Cl. 84-113) ABSTRACT OF THE DISCLOSURE A stringed instrument of guitar-like configuration is employed which includes 21 fret board. The normal fret board includes fourteen frets, one note for each fret, and six strings. One oscillator per string is provide-d, and the oscillators are keyed on individually, and tuned, on concurrent closure of both fret and string switches, or the latter alone, for any string. This action produces output frequencies, depending on which frets are played, except that the string switches alone produce open string pitches. Unless a string switch is actuated no tone results from its oscillator. The frequencies generated are in three footages, 4-foot, 8-foot and 16-foot. The 4-foot pitch is generated by a master oscillator, the 8-foot pitches by frequency division by a factor of two, providing tones an octave below, and the 16-foot pitch tones two octaves below, by a further division stage. The latter pitches are obtained at all times by frequency division of the output of each master oscillator, while that master oscillator is operating. The 2-foot and 32-foot pitches may also be included by using the same techeniques. The three footages are individually summed by a resistive summing network and applied to tone color filters, selected by means of tone color tabs. The outputs of the filters are summed on a header line, amplified and acoustically radiated.

The present invention relates generally to musical instruments and more particularly to electronic organ-like instruments having a keyboard incorporated on the neck of an ins-trument of generally guitar-shaped configuration, and utilizing electronic facilities for modulating, forming and producing tones.

It is well-known to provide a guitar-like instrument, in which pressure on the strings of the instrument serves to close circuits for selective tuning of oscillators. Such an instrument is disclosed in the US. patent to Donahue, No. 2,792,738, issue-d May 21, 1957, and may be designated an electronic guitar. The latter is not designed to simulate guitar tones when operated as an electronic guitar, but the tones are provided by the oscillators and the instrument acts merely as a vehicle for the circuit cl-osing devices.

-In accordance with the present invention, key switch actuators are provided in the positions of the frets of a guitar-like instrument, so that they may be actuated by the same fingering as is normally employed to finger the strings of the instrument. The switches serve to tune oscillators, one per string, to frequencies appropriate to the fret positions of the instrument.

Accordingly, the guitar-like instrument m-ay be fingered in normal fashion. The oscillators issue signals at frequencies equal to the fundamental frequencies of the tones which would have been generated by the instrument had it been played in normal fashion. The instrument may be played in relatively normal fashion, i.e. rolling over sounding tabs of the instrument, which also control open string tones. The sounding tabs are located for convenient control by the right hand of a player, who can simulate plucking of strings in actuating the tabs. The presently preferred embodiment of the instrument omits strings.

The outputs of the oscillators, in accordance with the invention, may be converted to various organ footages, as desired, and applied to tone color filter circuits of the types conventionally employed in electronic organs. The tone color circuits may be selected by tone color tabs. Appropriate circuitry may be included to provide not only a variety of tone colors, but also attack and decay characteristics similar to those of a normal guitar, so that the latter instrument may be simulated.

The strings of the guitar, and similar instruments, such as the banjo, mandolin or balalaika, for example, are plucked by the right hand, while tones are selected by the fingers of the left hand. According to the invention, sounding tabs are provided, one per string, which perform an equivalent of the plucking function. The sounding tabs actuate switches which, if alone actuated for any string location, cause an open string n-ote to be sounded for that string location. If a key switch for that string is also actuated its tone supersedes the open string tone. But no tone at all is sounded unless the sounding tab is depressed. The sounding tabs may, accordingly, be plucked selectively or in combination, to form chords, by an action similar to that required to pluck the strings of the true guitar. Similarly to the action of the latter, if only a sounding tab is plucked, but the appertaining string is not fingered, an open string sound results, while if the string is fingered a tone c-orresponding with the finger position results. The key switches of a string supersede each other in the order of frequencies, so that if two or more switches are simultaneously depressed, for a string position, only that one of the switches which generates the highest pitch is operative.

It is, accordingly, a primary object of the invention to provide a system for generating electronic organ tones originated in response to fingering and plucking of a guitar-like instrument, in accordance with the technique appropriate to the instrument, or a reasonable simulation of such technique.

Briefly describing a preferred embodiment of the invention, a stringed instrument of guitar-like configuration is employed which includes a fret board. The normal fret board includes fourteen frets, one note for each fret, and six strings. One oscillator per string is provided, and the oscillators are keyed on individually, and tuned, on concurrent closure of both fret and string switches, or the latter alone, for any string. This action produces output frequencies, depending on which frets are played, except that the string switches alone produce open string pitches. Unless a string switch is actuated no tone results from its oscillator. The frequencies generated are in three footages, 4-foot, 8-foot and 16-foot. The 4-foot pitch is generated by a master oscillator, the 8-foot pitches by frequency division by a fractor of two, providing tones an octave below, and the 16-foot pitch tones two octaves below, by a further division stage. The latter pitches are obtained at all times by frequency division of the output of each master oscillator, while that master oscillator is operating. Of course, the 2-foot and 32-foot pitches may also be included by using the same techniques.

The three footages are individually summed by a resistive summing network and applied to tone color filters, selected by means of tone color tabs. The outputs of the filters are summed on a header line, amplified and acoustically radiated.

It is an object of the invention, accordingly, to provide an electronic guitar having plural footages, tone generators and tone color filters, wherein the tone generators comprise tunable master oscillators, one per string of the instrument, and wherein actuation of switches located at the fret positions and plucking positions of the instrument, in a manner suitable to the simulated instrument, serves to tune the associated master oscillators to appropriate frequencies. It is a broader object of the invention to provide an electronic organic in which key switches are associated with the neck of a stringed instrument, so that the organ may be played according to playing techniques appropriate to the instrument, rather than in the fashion normal for an organ.

It is a further object of the invention to provide an electronic organ playable as a fingered instrument, of the type having no keyboard, such as a guitar, or other stringed instrument, in which one tunable oscillator is provided for each string of the instrument, each oscillator being tunable to an appropriate frequency on actuation of switches located at a fingering position of the instrument, and at its plucking position, or the latter alone, the plucking position alone providing an open string note.

It is still another object of the invention to provide an electronic organ capable of playing chords, and employing a small number of tunable oscillators, each to provide one tonal component of any chord.

Another object of the invention is to provide an electronic stringless instrument, played like, and simulating the percussive tones of a stringed instrument.

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of one specific embodiment thereof, especially when taken in conjunction with the accompanying drawings, wherein:

. FIGURE 1 is a block diagram of a system according to the invention;

FIGURE 2 is a. schematic circuit diagram of a tone generator, employed in the system of FIGURE 1;

FIGURE 3 is an equivalent circuit diagram of an oscillator according to the invention, showing transistor parameters;

FIGURE 4 is a simplified equivalent circuit diagram of the oscillator of FIGURE 3;

FIGURE 5 is a phasor diagram of the oscillator of FIGURE 4;

FIGURE 6 is a view in side elevation of keys and switches employed in the invention;

FIGURE 7 is a view in perspective of a complete instrument, illustrating its appearance and the location of its switch actuators;

FIGURE 8 is a block diagram of a modification of the system of FIGURE 1; and

FIGURES 911, inclusive, are schematic circuit diagrams of keying and gate circuits incorporated in the system of FIGURE 8.

Referring now to FIGURE 1 of the drawings, the reference numerals 10-15, inclusive, represent individual sets of fret and string switches, each set being associated with one of the strings of a guitar, or other instrument of similar character. The reference numerals 16-21 represent tone generators which are selectively keyed and tuned by the keys 10-15, respectively, to frequencies appropriate to the switches.

As will appear hereinafter, each set of switches actually includes fourteen fret switches, each representing a fingering position, plus one string switch representing open string condition. A lesser number is shown solely to simplify the diagram. The string switch, when actuated alone, tunes the oscillator to open string frequency. When operated in conjunction with any fret switch it enables the latter to control frequency. The fret switches however, each disable all fret switches pertaining to lower frequency tones for any string, so that actuation of more than one fret switch pertaining to one string results in sounding of only the note pertaining to the switch controlling the higher p-itch. No note sounds, for any string, except while its string switch is closed.

Each tone generator, as 16, includes a tunable oscillator and two frequency dividers driven by the oscillator. Thus every tone generating action results in the simultaneous generation of three footages, i.e. 4-foot, 8-foot and 16- foot.

In addition, each tuning generator includes means for tuning the entire string of notes keyed by the fret switches, over a range of approximately two semi-tones in either direction. This is accomplished by tuning a slug-tuned coil 36 (FIGURE 2).

The outputs of the generators are summed, in terms of separate footages, in a resistive summing board 22, of conventional configuration, and applied to the inputs of a plurality of tone color filters 23. The latter are selected at their outputs by tab switches 24, and the selected tones applied to a first preamplifier 25, having a conventional tone control 26, and a second preamplifier 27 having an expression control 28. The output of the latter is amplified by power amplifier 29 and radiated acoustically by loudspeaker 30, or the like.

The tone colors provided for one specific embodiment of the invention are:

Tibia-16 Tibia8' Salicional-8' Saxophone-8' Clarinet--8' Oboe horn-8 Tibia-4 Silicet-4' Referring now to FIGURE 2 of the accompanying drawings, wherein is illustrated a single tone generator associated with one string of the stringed instrument of the present invention, the reference numeral 31 denotes a string switch, one contact of which is grounded and the contacts of which are normally open. String switch 31 controls open string frequency of oscillator 32 and in addition it must be closed in order that an oscillator 32 may oscillate at all. The fret switches 33, of which only four are illustrated for the sake of simplification, are normally closed in series with one another, at contacts 34, the last of which leads to one end 35 of a multisection coil 36, via a resistance R It follows that when string switch 31 alone is closed ground is conveyed to end 35 of coil 36, this being the open string condition of the oscillator. The remaining end 38 of coil 36 is coupled via coupling capacitors C and C to the collector 42 and the base 43 of a transistor 44, having a grounded emitter 45.

Connected between collector 42 and base 44 is a re sistance 46, which sets bias. The collector 42 is connected via resistance 47 to a negative DC supply 48. The switch contacts 50, 51, 52, 53, respectively, of switches 33 represent stationary contacts of fret switches for a single string, there being fourteen in all, in an actual guitar-like instrument, but only four being illustrated to simplify the presentation. The contacts 50-53, inclusive provide separate resistances R5, R4, R3, R2, respectively, in series with appropriate taps on coil 36. Actuation of a single switch armature of any of switches 33, accordingly, connects an associated tap 55 to ground, through the circuit subsisting between the selected switch, switch 31, and normally closed contact 34. The string key 31 must be closed concurrently with any fret switch, in order to complete the ground circuit, so that a selected portion of coil 36 is connected in circuit with oscillator 32, on closure of each fret switch, provided the grounding switch 31 is also closed. The latter switch, when closed alone, leaving all switches 33 unactuated, tunes oscillator 32 to open string condition and renders it oscillatory and operative. All other switches, except the switch corresponding to the note of highest pitch played, are disabled, since the switches 33 are double pole switches and when operated, each switch breaks the circuit to ground via switch 31, for all switches of lower tone value.

If desired, vibrato effects may be obtained by connecting a conventional 6-8 c.p.s. oscillator (not shown) to the vibrato input.

The criteria for the master oscillators, 32, are that they 5 shall be (1) small and compact (2) stable (3) variable in frequency over the required range without appreciable loading (4) have a wave form suitable for triggering a divider stage (5) be susceptible of keying. The oscillator 32 is a phase shift LC oscillator in which C is a feedback element. The effect of C is to by-pass very high ringing frequencies. Frequency is determined by f 1 The equivalent circuit of the oscillator, FIGURE 3, is drawn utilizing the so-called hybrid parameters. C may be neglected because of its previously noted limited effect. Further, h V may be neglected because voltage gain of the oscillator is small. Also, h. may be neglected because it is the reciprocal of a resistance value ranging from 5K to 100K, large in comparison to load resistor r Similarly, bias resistance rb is large compared to input resistance h .By neglecting the insignificant components, the equivalent circuit diagram may be simplified to that of FIGURE 4. The hybrid equations become:

l= i :1+ r o i i i o= i t+ o o h i By definition l r By measurement of transistor parameters and insertion 'of the measured values in the above equations, it becomes possible to write Beta (5) falls in the range 20200 and I is about 8 ma. Assuming a B of 100.r =675Q which places C C and and r in parallel.

The phase shift relations in the oscillator may be explained by reference to FIGURE 5, wherein V, is the voltage across the tank circuit. The current i, through the capacitor C, leads this voltage by some value less than 90, and in magnitude is proportional to h i Across the resistance r exists an output voltage, s which is 180 out of phase with h i and this voltage exists across a RLC series circuit, producing a lagging voltage V across C of less than 90. The voltage across the tank circuit V at the oscillating frequency is 180 out of phase with V and therefore in phase with V When loop is gain is such that V =V the circuit oscillates. Tuning of the oscillator is accomplished by tapping along inductance L, which in a practical embodiment of the invention includes 15 taps. Fine tuning of the frequency can be accomplished by adjusting resistors R to R (FIGURE 2). The use of a resistance to adjust tuning is an important feature of the invention, since it is virtually impossible to select taps which accurately provide the required set of frequencies, due to the effects of stray capacities and copper losses, hysteresis losses and those due to residual induction.

Returning now to FIGURE 2 the output of the oscillator comprising transistor 32 is applied to a trigger amplifier 60, of conventional character, and the output of the latter triggers a first flip-flop divider, 61, of conventional character, and the latter in turn a second similar divider 62. Accordingly, three footages are generated, one deriving at terminal 65 of trigger amplifier 60, one at output terminal 66 of first divider 61, and another at output terminal 67 of second divider 62. The terminals 65, 66, 67 are illustrated as parts of the generators of FIGURE 1, which also illustrates the resistance matrix 22, which sums the outputs of the same footage from the several generators, on leads 70, 71, 72, for application to the tone forming filters 23.

FIGURE 7 illustrates the appearance of a guitar-like instrument according to the invention. On the neck of the instrument, at its fret positions, are arranged keys 81. The keys 81 occupy positions in longitudinal rows of fourteen, each row corresponding with one string of a conventional guitar, and each key being located at a fret position for that string, so that a total of six rows is employed. In addition, and located adjacent a plucking position, is a transverse row of keys 82, one for each string. The keys 82 actuate the string switches 31 (FIGURE 2) and the keys 81 actuate the fret switches 33. Stop tabs 85 are provided to select filters 23 (FIGURE 1) for tone forming purposes.

The arrangement of the keys and their relation to the key switches are made evident on consideration of FIG- URE 6. The keys of a transverse row are all pivotally mounted on a rod 90. Under each key is located a double throw switch, constructed of wire, the contacts 34, 50 being stationary and the contact 33 being movable, and normally in circuit with contact 34, when key 80 is raised, but with contact 50 alone when key 80 is depressed (see FIGURE 2).

The system of FIGURE 1 may be considerably improved by the addition of keying and gate circuits as shown in FIG. 8. For purposes of simplification the complete switching circuit is not shown in FIGURE 8, but it is to be understood that the switching circuit configuration employed is the same as that shown in FIGURE 2 with the exception that string switch 31 is by-passed, i.e., short-circuited and a gate switch 31 is associated with key 82 (FIGURE 7). Thus, in the embodiment of FIG- URE 8, each tone generator, as 16, is continuously operative by virtue of a completed path to ground through short-circuited string switch 31. However, this alone does not produce sound output, for the reason that each of the footage terminals 65, 66, 67, leads to a separate gate, as 102, 103, 104. Each gate is normally closed so that no tone can pass through the gate until a control signal is applied thereto. To this end, a keying circuit, as 100, is connected between the gates, 102, 103, 104, and a gate switch 31. Upon closure of the gate switch 31, supply voltage is applied to keying circuit which in turn energizes, i.e., opens, one of the gates to allow a particular tone signal to pass, and thus provide a sound output.

The keying circuit, either alone or in conjunction with the gate, may further be used to provide envelope control, i.e. control of onset and decay, of the generated tone. For example, it may be desired to provide a slow buildup of the tone, or a rapid buildup followed by a slow decay to simulate percussive elfects, appropriate to the guitar, or to produce sustain effects, or the like. If the instrument is to simulate a banjo, instead of a guitar, the gate switch 31 may energize a multivibrator, as 160 in FIGURE 10, to supply recurrent keying voltages to the gating circuit, while switch 31' is closed, at a rate appropriate for simulating the picking of a banjo string.

Examples of keying circuits are provided in FIG- URES 9 and 10 and of a gating circuit in FIGURE 11.

In FIGURE 9, the negative voltage applied on closure of switch 31' for application to the gate, say 104. A shunt circuit 109 to ground exists, from lead 107, which contains a capacitor 110 and a switch 111. When switch 111 is closed, and switch 31' also closed, the capacitor 110 acquires a charge to V volts. When switch 31 opens this charge is dissipated through the gating circuit, exponentially, providing a gradual decay of the output signal of the gate, known as a sustain.

For percussive effects the system of FIGURE 10 is employed as a keying system 100, in conjunction with the gate 104 of FIGURE 11.

Turning now to the gate 104, a circuit exists from input terminal 120, Via capacitor 121, diodes 122, 123 to a is directed on a lead 107 to terminal 108,

load resistance 124 and an output terminal 125. The latter leads to summing network 22.

The diodes 122, 123 are connected with their cathodes in the direction of terminal 120. A parallel resistance and capacitance circuit 126 is connected between the junction of diodes 122, 123 and ground.

The signal supplied to terminal 120 is an AC tone signal. The diode 122 constitutes a half wave rectifier. Accordingly the capacitor 121, having 'no leakage path, acquires a positive potential at the cathode of diode 122 equal to the negative peak value of the tone signal, and thus biases diode 122 to cut-off. No tone signal can pass, normally, i.e. in absence of keying voltage.

Since a diode does not have infinite reverse resistance, some signal leaks through. This is by-passed by circuit 126 and blocked further by diode 123.

Upon application of negative keying voltage to the cathode .of diode 122, from keying voltage terminal 130 and high resistance 131, the diode 122 is unblocked, which also unblocks diode 123, and the negative voltage so applied is sufficiently great to permit the entire tone wave shape on terminal 120 to pass through. However, the discharge of capacitor 121 and its recharge in opposite sense, which occurs when negative gating voltage is applied to terminal 130, requires time, dependent on the time constant of resistance 131 and capacitor 121, which provides, if desired, a relatively gradual rise of the tone amplitude and thus avoids key clicks.

The keying circuit of FIGURE 10, in response to closure of switch 31, applies negative voltage instantaneously through diode 139 to terminal 140, in the process charging capacitors 141, 142 and discharging capacitor 121, rendering diodes 122, 123 conductive. Across the latter, then appears the required negative gating voltage, whereby the gate 104 is turned on and passes signal.

Diode 143, which extends at its anode to the cathode of diode 139, and at its cathode to ground, passes no negative current.

While capacitor 142 acquires an instantaneous high negative potential with respect to ground, the keying voltage proceeds via capacitor 141 and diode 139 to terminal 140, and thence to terminal 130 (FIGURE 11) and through resistance 131 to the cathode of diode 122, rendering the gate conductive. This process is delayed by the fact that combination of capacitor 121 and resistance 131 involves a time constant, which, however, can be small.

Upon opening the switch 31, the left hand plate of capacitor 141 tends to go to ground potential. Capacitor 141 can now discharge through diode 143 and resistance 144, since the potential of capacitor 141 considered as a source tends to drive current towards the cathode of diode 143. The capacitor 141 cannot discharge through diode 139, because it is biased off by'capacitor 142.

Capacitor 142 now proceeds to discharge through resistance 131, the resistance of circuit 126 and the resistance of the load 124. This represents a long time constant circuit. The discharge gradually drives the cathode of diode 122 toward ground, whereupon the capacitor 121 proceeds to recharge in an oil? bias direction for diode 122, in response to generator current and the rectifying action of the diode 122. This continues until the cycle is complete,

For the specific keying circuits and gates employed, others may be substituted, and the disclosed circuitry is intended to be exemplary only.

If desired a multivibrator 160 can be connected to input terminal 145 of the keying circuit of FIGURE instead of -V, to produce banjo or mandolin effects.

While I have described and illustrated one specific embodiment of my invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope of the invention as defined in the appendt d claims,

I claim:

1. An electronic musical instrument which simulates a plucked string instrument, comprising a separate row of switches for each of the string positions of said instrument, a separate oscillator for each of said rows, means responsive selectively to actuation of only the switch of highest pitch for each of said rows for tuning the oscillator pertaining to that string to a frequency appropriate to said switch of highest pitch, a string switch for each of said rows, each string switch when unactuated disabling its row and when actuated enabling its row to control the frequency of the oscillator pertaining to that row, said string switch when actuated to the exclusion of any other switch of its row tuning the oscillator pertaining to its row to an open string pitch, said rows of switches being located on said instrument for operation by fingering the instrument by one hand of a player and said string switches being located on said instrument for simulated plucking by the other hand of said player.

2. The combination according to claim 1 wherein each of said string switches when actuated completes a ground circuit for its oscillator, said string switches being open when in unactuated condition.

3. The combination according to claim 2 wherein the switches of each row of switches includes contacts normally closed in series with each other and with the normally open string switch pertaining to the row, the oscillator pertaining to the row having a tapped tuning ele ment, said row of switches taken in series being connected to the lowest frequency tap of said tapped tuning element, said row of switches having normally open contacts connected in sequence with the remaining taps of said tuning element.

4. The combination according to claim 1 wherein each of said oscillators is connected to a series of frequency dividers, means for combining the outputs of said frequency dividers to provide a harmonic rich tone for each frequency of each of said oscillators, and tone forming filters connected in cascade with said means for combin- 5. An electronic musical instrument simulating a plucked string instrument, comprising a single oscillator substituted for each of said strings, fingering means for tuning said oscillator over the gamut of musical tones in simulation of fingering of the strings of said instrument, said oscillators being normally disabled, and means responsive only to simulated plucking of each of said strings for placing the corresponding oscillator in oscillating condition.

6. In combination, in an electronic system which simulates a string instrument, a tunable oscillator, a plurality of key operated switches connected to said oscillator and arranged each to tune said oscillator to a different musical frequency when actuated, said oscillator being normally disabled, and a further switch operative when actuated for both enabling said oscillator and tuning said oscillator to a musical frequency different from the first mentioned musical frequencies.

7. The combination according to claim 6 wherein said further switch is located in plucking position on said instrument and said key operated switches are located at fingering positions of said instrument.

-8. The combination according to claim 7 wherein said last named musical frequency is an open string frequency and said first mentioned frequencies are fingered frequencies of said string.

9. The combination according to claim 8 wherein is provided means for disabling all said key operated switches from tuning said oscillator except the key switch of highest musical frequency.

10. The combination according to claim 9 wherein said key switches are double throw switches, having two stationary contacts and a movable contact, one stationary contact of each of said switches and its stationary contact being normally closed in series with said further switch,

said further switch being normally open, said normally closed contacts being connected in an array in series with each other and with said further switch, a tapped tuning element for said oscillator, said further contacts being connected to the taps of said tapped tuning element in predetermined order, said further switch when closed completing a circuit to ground for said array.

11. In combination, in an electronic musical instrument simulating a plucked string instrument, a separate oscillator -for simulating the tones of each of the strings of said plucked string instrument, means responsive to simulated fingering of said strings for tuning said oscillators, said oscillators being continuously operative, and means, including a separate wave shaping facility for each of said oscillators, responsive to simulated plucking of said strings for selectively controlling the emission and sound efiects of said tones.

12. The combination according to claim 11 wherein said means for tuning said oscillators includes a plurality of fret switches for each of said strings, and wherein said means for selective control includes a gate switch for each of said strings, a separate gating circuit connected in cascade with each of said oscillators, and a separate keying circuit responsive to each of said gate switches for energizing each of said gating circuits, said keying circuits including said wave shaping facilities.

13. The combination according to claim 11 wherein said wave shaping facilities'include percussive wave shaping facilities.

14. The combination according to claim 12 wherein said wave shaping facilities are percussive wave shaping facilities.

15. In combination, in an electronic musical instrument which simulates a non-electronic instrument having provision for fingering, comprising a plurality of oscillators, each covering a different limited portion of a total gamut of musical sounds, said oscillators being individually tunable each over its portion of said gamut in response to said fingering independently of the remaining oscillators, whereby said oscillators are capable of producing single tones or chords at will, wherein said non-electronic instrument is a stringed instrument and each of said oscillators individually pertains to and is tunable over the available pitches of a difierent one of said strings, and wherein is included provision for rendering said oscillators normally inoperative, and means exclusive of said fingering for rendering said oscillators operative in any combination at will.

16. The combination according to claim 15 wherein said fingering pertaining to any oscillator is operative to tune said oscillator only to the highest pitch requested by said fingering, when said fingering is multiple.

References Cited UNITED STATES PATENTS 2,070,344 2/1937 Waters 841.27 2,792,738 5/1957 Donahue 84-116 3,196,201 5/1965 McDonald 84-126 3,207,952 9/1965 Brahrn 84-126 ARTHUR GAUSS, Primary Examiner. B. P. DAVIS, Assistant Examiner. 

1. AN ELECTRONIC MUSICAL INSTRUMENT WHICH SIMULATES A PLUCKED STRING INSTRUMENT, COMPRISING, A SEPARATE ROW OF SWITCHES FOR EACH OF THE STRING POSITIONS OF SAID INSTRUMENT A SEPARATE OSCILLATOR FOR EACH OF SAID ROWS, MEANS RESPONSIVE SELECTIVELY TO ACTUATION OF ONLY THE SWITCH OF HIGHEST PITCH FOR EACH OF SAID ROWS FOR TUNING THE OSCILLATOR PERTAINING TO THAT STRING TO A FREQUENCY APPROPRIATE TO SAID SWITCH OF HIGHEST PITCH, A STRING SWITCH FOR EACH OF SAID ROWS, EACH STRING SWITCH WHEN UNACTUATED DISABLING ITS ROW AND WHEN ACTUATED ENABLING ITS ROW TO CONTROL THE FREQUENCY OF THE OSCILLATOR PERTAINING TO THAT ROW, SAID STRING SWITCH WHEN ACTUATED TO THE EXCLUSION OF ANY OTHER SWITCH OF ITS ROW TUNING THE OSCILLATOR PERTAINING TO ITS ROW TO AN OPEN STRING PITCH, SAID ROWS OF SWITCHES BEING LOCATED ON SAID INSTRUMENT FOR OPERATION BY FINGERING THE INSTRUMENT BY ONE HAND OF A PLAYER AND SAID STRING SWITCHES BEING LOCATED ON SAID INSTRUMENT FOR SIMULATED PLUCKING BY THE OTHER HAND OF SAID PLAYER. 